Bending brass tubing

[vlmarshall]

For bending thin wall brass tubing try anealing it and filling it with Bismuth. Works for me.

I really HAVE to try that, I have a lot of low-temp alloy left over from some miniatures casting I used to do.

 

[VirginiaGuy]

You have to heat it to barely glowing red hot in dim light.

 

[Tin Falcon]

IIRC k & S sells spring benders as well.

Only a couple dollars

http://hardwareonlinestore.com/

Wow that was an old thread that was dug up !

VirginiaGuy please post an introduction in the welcome area. and tell us a bit about yourself.

Tin

 

[user 10585]

I bend 1/8" brass tubing by first annealing it then putting a piece of plastic weed eater string thru it, that keeps it from collapsing when bending,. Then pull it out when done.

 

[stevehuckss396]

Hello Fellows!!

I saw this post brought back to life and I sort of had to laugh. I posted this over 5 years ago. I'm happy to report that bending tubing is not a problem anymore. I typically make a shoe for the tubing size. I also switched to stainless tubing because it looks great after a good polish and bends easily.

 

[davidyat]

I haven't used it but I hear Cerrobend could work in bending tubing. It's a low melting metal. It melts into liquid form at 158 degrees Fahrenheit. If you can find a stick of it that will fit into your tubing, stick it in and with one end capped somehow, put it into a pot of boiling water. After it solidifies, bend your tubing and stick it into boiling water again to get the Cerrobend out.

https://www.ebay.com/itm/Cerrobend-...IoAAOxyc2pTaiqe:sc:USPSFirstClass!46123!US!-1

 

[deverett]

I've heard that it is a good idea to 'line' the pipe with olive oil or similar to ensure that there is no residual CerroBend left afterwards. Or was that when using other types of filler?!

Dave
The Emerald Isle

 

[bobden72]

I have used Cerrobend quite a few time and can say without a doubt its great. Don't forget you still have to anneal the tubing before.

 

[Cogsy]

I've heard that it is a good idea to 'line' the pipe with olive oil or similar to ensure that there is no residual CerroBend left afterwards. Or was that when using other types of filler?!

Dave
The Emerald Isle

I use the olive oil and it was my understanding that it's to prevent the cerrobend sticking to the wall of the pipe while you bend it. If the cerro is stuck firmly to the pipe it can fracture as you bend the pipe and leave 'steps' in your bend. With it's low melting temp I wouldn't expect the cerro would be a problem to get out of the tube even without the oil layer.

 

[bluejets]

Hello Fellows!!

I saw this post brought back to life and I sort of had to laugh. I posted this over 5 years ago. I'm happy to report that bending tubing is not a problem anymore. I typically make a shoe for the tubing size. I also switched to stainless tubing because it looks great after a good polish and bends easily.

Hi Steve,
Do you have any detail on the tubing sizes and where you manage to get it from?
Down under these things are hard to come by normally.
Maybe a tooling tip on how you make your mandrels if you get a chance one day.
Cheers Jorgo

 

[WOB]

Cerrobend is intended to "stick" to the wall of the tubing. It does this by expanding as it cools. If the rod of Cerrobend is allowed to slip as the tube is bent, it will break( it is relatively brittle) and slide, opening up a gap and allowing the tube to distort at the gap which is usually at the apex of the bend. I learned this the hard way by trying to bend 5/16" soft aluminum tube with Cerrosafe that I had on hand. Cerrosafe does not expand on cooling until some time has passed and then not very much long term. I found that if I aged my Cerrosafe filled tube for 24 hours I then could bend them safely. Cerrobend allowed immediate bending on cooling and I could get on with the job. Well worth the additional small expense.

WOB

 

[Ken I]

Here's a link to a bender I posted some time back....

https://www.homemodelenginemachinist.com/threads/wire-tube-bender.16140/

Regards, Ken

 

[stevehuckss396]

George britnell also posted some plans for a super nice tubing bender. Do a search but I think they are in the files archives.

 

[stackerjack]

I've heard that it is a good idea to 'line' the pipe with olive oil or similar to ensure that there is no residual CerroBend left afterwards. Or was that when using other types of filler?!

Dave
The Emerald Isle

Another idea is to use electrical flex. Remove the outer sheath from a suitable piece of electrical flex then cram as many strands as possible inside the tube, as tight as possible. Bend the tube, then withdraw the flex one strand at a time.
Jack

 

[bluejets]

George britnell also posted some plans for a super nice tubing bender. Do a search but I think they are in the files archives.

So do you have any detail on the tubing sizes and where you manage to get it from?

 

[bobden72]

I've heard that it is a good idea to 'line' the pipe with olive oil or similar to ensure that there is no residual CerroBend left afterwards. Or was that when using other types of filler?!

Dave
The Emerald Isle

Dave never had a problem getting the CerroBend out of the tube. Instructions don't mention a release agent.

 

[kquiggle]

Here are some "official" instructions for using cerrobend:

http://www.csalloys.com/how-its-made.html​

Here's an excerpt, but check the link for additional details and useful information:

Directions for bending thin walled tubing with CS Alloys

1. Make sure that tubing is fully annealed.
2. Clean interior of tube with pull-through to remove any scale or foreign matter.
3. Tightly plug one end of tube with wood or rubber plug.
4. Fill tube with a light grade oil, preferably S.A.E. 10.
5. Pour oil from tubing leaving a small amount in the bottom of the tube. Careful attention to oiling is necessary to prevent the CS Alloys “tinning” the tube.
6. Fill tube with CS Alloys from an iron ladle or a welded stainless steel container suspended in boiling water or hot water jacketed stainless steel tank, allowing the alloy to run down the side of the tube in order to avoid air pockets. Small tubes (1/4” dia. or less) should be placed in boiling water while being filled.
7. Lower loaded tube immediately into a cold circulating water quenching tank and leave for sufficient time for tube and filler to attain room temperature throughout (About 15 minutes for 1” diameter tubing, 20 minutes for 1-1/2” diameter tubing, etc.).
8. After proper quenching, re-warm loaded tubes to about body temperature.
9. Remove plug from tube.
10. Bend loaded tube with a slow uniform pressure over a forming block or in a regular bending machine.
11. Immerse bent tube in boiling water tank (stainless steel preferred) and allow CS Alloys to run out (Do not use torch). Tilt and shake tube as necessary to remove alloy as completely as possible.
12. Plunge unloaded tube, while still hot, in cold water for two minutes to solidify and small drops of CS Alloys retained in the oil film.
13. Flush tube with a cold grease solvent to remove oil film and any solid particles of CS Alloys. Additional cleaning may be done with a tight fitting pull-through.

Important: Satisfactory results depend entirely on rapid quenching and thorough cooling, re-warming before bending, and using a slow uniform pressure during the forming operation.​

 

[WOB]

These instructions are overkill for the small tubing used by modelers. Aluminum and stainless tube will not "tin", so do not oil them. I have not used Cerrobend on copper or brass tube, but at the low temps. involved, I do not see how tinning could occur. Also don't need the elaborate cooling procedure. Simply cool to room temp. and bend them. After bending and immersion in boiling water, simply push a pipe cleaner through the tube and any residual metal will push out. Most of the time here will not be any left in the tube.

WOB

 

[stevehuckss396]

So do you have any detail on the tubing sizes and where you manage to get it from?

https://www.homemodelenginemachinist.com/threads/tube-bending-radius.7810/#post-86271

 

[kquiggle]

WOB - you make some very good points.

My starting assumption is that the guys who make and sell Cerrobend must know something about how to use it, but it's also good to bear in mind that their target audience is not the hobby machinist. I think this is true in many cases, where advice or instructions developed for production environments have to be adapted or modified to fit the home workshop. However, I do think it is useful to have a solid and well informed starting point, and then adapt as necessary.

Now that I have read the Cerrobend instructions, I better understand why oiling is necessary in some cases (and as you rightly point out, not always needed). It is in any case an interesting alloy and I had fun learning more about it.